RESUMEN
BACKGROUND: Hypertrophic cardiomyopathy (HCM) in neonates is a rare and heterogeneous disorder. HCM accounts for 25 to 40% of all pediatric cardiomyopathy cases and the highest incidence in pediatric population is reported in children < 1 year. CASE PRESENTATION: we report two clinical cases of neonates, born to mothers respectively with a pre-pregnancy insulin-dependent diabetic mellitus type 2 and a suspected diabetes, with inadequate prenatal glycemic control for the first and underestimated glycemic control for the second case, with a different evolution. In the first case, a slow evidence of improvement of the HCM was observed, persuading us to the diagnosis of a diabetes-related HCM; In the second case the progressive worsening of the HCM during follow-up in association with further investigations, resulted in the diagnosis of Pompe disease. CONCLUSIONS: Hypertrophic cardiomyopathy in newborns can be the clinical expression of different underlying disorders. We aim to show the importance both to reassess maternal and family history and critically evaluate the physical examination in order to address the correct differential diagnosis. Furthermore it is important to continue a regular cardiologic follow-up for this pathology with neonatal onset to prevent a poor prognosis.